1. Field of the Invention
The present invention relates to photographic processing equipment. In particular, the invention relates to a holding device for securing a photographic paper roll core concentrically about a rotatable shaft.
2. Description of the Prior Art
Photographic prints are typically made from photographic film negatives. Such prints are made on photographic paper which is manufactured and handled in bulk rolls. These rolls are usually carried on a central hub or core of suitable rigid material, such as cardboard or plastic. In making such prints, the core and roll of photographic film mounted thereon are positioned on photoprocessing equipment (such as a photographic print cutter) so that the photographic paper may be unrolled or unwound from the core for processing purposes. Thus, the core must be secured to a rotatable shaft to permit the uniform unwinding of the photographic paper thereon.
Prior art devices for securing such cores on shafts were cumbersome in use and slow to activate. They generally included a plurality of resilient rings and rigid spacers alternatively positioned concentrically about a rotatable shaft with a nut or clamping ring threadably mounted on the end of the shaft which could be tightened down against the rings and spacers to expand the rings radially outwardly from the shaft and for gripping the paper roll core. A plurality of resilient rings was required on these devices because of the need for gripping different sizes of paper roll cores (for different widths of photographic paper). The need for a plurality of resilient rings caused several problems with such devices. For instance, with constant use, the ring concentricities would become misaligned, thus making it difficult to quickly and easily slide the cores on and off of the holding device because it would become hung up on the misaligned rings. In addition, when clamping a core of narrow width, the outermost resilient rings would necessarily be forced to be fully compressed (to "bottom out") before the inner ring(s) gripping the core would be deformed, thus requiring more time to tighten the nut or clamping ring on the rotatable shaft. Additionally, the only way to tell whether the paper roll core was secured to the rotatable shaft was by "feel" of the operator, depending mainly on how tight that operator could secure the nut or clamping ring on the shaft.
The prior art holding devices have been inconsistent with high production photographic processing. Excessive operator time is required to position and secure the paper roll core on the rotatable shaft, and even then, the degree of securement of the core is dependent upon the operator's strength and sense of feel.